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M L Cheal

Publications and source records attributed to M L Cheal.

15 recordsLinked to original sources
PubMed1999

Attention effects of abrupt-onset precues with central, single-element, and multiple-element precues.

Endogenous and exogenous processes of attention have been inferred with different types of precues used in allocation of attention to a target location. In the present research, a comparison was made between the typical peripheral single-element precue (SEP), a central precue, and a multiple-element precue (MEP) in order to further understanding of the processes involved in allocation of attention. Two precues were used on each trial in these experiments. An abrupt-onset precue appeared with an SEP, an MEP, or a central precue and was followed 50 or 300 ms later by a screen containing a target and two distractor characters. The abrupt-onset precue and the other precue each could be valid or invalid in indicating the location of the target, as in the study by Juola, Koshino, and Warner (1995). Response times to the targets showed that validity effects of the abrupt-onset precue and the MEP or central precue were additive, whereas those of the abrupt-onset precue and the SEP were interactive. These data suggest that, like a central precue, an MEP is an endogenous precue that guides conscious control of attention and has its attentional effects at a different processing level from an SEP, which is an exogenous precue and may compete for attentional resources with an abrupt-onset precue.

Adolescent↗
PubMed1997

Evidence of limited capacity and noise reduction with single-element displays in the location-cuing paradigm.

Precuing a location facilitates accuracy of identification of a target at that location and reduces noise from other nontarget characters in a multicharacter field. In 5 experiments, evidence for facilitation included higher accuracy with long precue-target intervals than with short intervals and higher accuracy when a precue indicated the correct location than with short intervals and higher accuracy when a precue indicated the correct location than when it indicated the wrong location. These results were found for each target-mask condition used (1 target with 1 mask, 1 target with 4 masks, or 1 target and 3 nontargets with 4 masks) in experienced and inexperienced observers. Evidence for noise reduction was found because accuracy was higher in the 1 target-1 mask condition than in the other conditions on correctly cued trials with short-cue-target intervals and on incorrectly cued trials. Data are related to methodological factors that are important to obtaining these effects and to capacity and noise reduction models.

Adolescent↗
PubMed1992

Benefits from attention depend on the target type in location-precued discrimination.

In previous research, we found that precuing of attention to a target location greatly improved discrimination of targets that differed in line arrangement, but had little effect on discrimination of targets that differed in line orientation. In the present research, a number of other targets that represent various feature differences were used. The new data are consistent with and extend our earlier findings by showing that (1) there is some effect of precuing with all targets tested, and (2) the size of precuing effects varies in a complex way with the nature of the target. Moreover, the difficulty of the discrimination cannot explain the size of the precuing effects. A framework for understanding the events occurring during trials in the location-cuing paradigm is presented and applied to these results.

Adult↗
PubMed1989

Attention effects on form discrimination at different eccentricities.

Considerable disagreement exists in the visual attention literature about how attention is allocated over the visual field. One frequently expressed metaphor is that attention moves like a spotlight, and in some variants it is assumed that attention takes longer to shift to targets further from fixation. In order to test this metaphor, five experiments were conducted in which target location was precued and form discrimination accuracy was assessed. By varying the interval between the precue and the target (stimulus onset asynchrony, SOA), a time course of attention effects was obtained for targets at 2 degrees, 6 degrees, and 10 degrees eccentricity. In the first three experiments, precueing effects were found, but there were no differences in performance as a function of eccentricity for very short SOAs, with either a peripheral cue or a foveal arrow cue. For long SOAs, however, performance was better for targets that were closer to fixation. In Experiments 4 (peripheral cue) and 5 (foveal cue), the targets were scaled to make them equally discriminable at all eccentricities. Again precueing effects were found, but there were no differences in accuracy as a function of eccentricity for most SOAs. These results suggest that attention shifting is not analogous to a constant-velocity moving spotlight.

Adult↗
PubMed1986

The gerbil: a unique model for research on aging.

The Mongolian gerbil (Meriones unguicultatus) is suggested as a model for aging research because of its unique physiological attributes, ease of handling, and because of data previously collected. Factors that demonstrate the gerbils' suitability in fulfulling practical and scientific considerations important in determining a model for aging research are listed. Additionally, several unique physiological attributes of gerbils are described. Based on these attributes and on review of research in gerbils, it is suggested that gerbils can serve as animal models for behavioral and biological processes, and for normative and pathological aspects for aging.

Adrenal Cortex↗
PubMed1984

Perseveration of attention to conspecific odors and novel objects in castrated gerbils.

Castrated male and female gerbils were tested for odor preference and for attention to conspecific odors and a novel object. Castrated gerbils housed with sham-operates preferred home odors, discriminated between two groups of male gerbils by olfactory cues, and perseverated in attention to odors of male gerbils and to a novel object. Similar perseveration to male conspecific odors was shown in gerbils given injections of L-DOPA (30 mg/kg). Combined treatment (castration and L-DOPA) resulted in additive effects on perseveration. This research challenges two general hypotheses of gonadal hormone function. The first, that changes in odor preference after castration are due to a loss in testicular androgen, is insufficient, because (1) female as well as male gerbils showed similar perseveration to odors, (2) there was a significant correlation between LH and duration of investigation of male conspecific odors, and (3) L-DOPA, the dopamine precurser, also caused perseveration to conspecific odors. The second, that gonadal hormones are responsible for persistence of attention, cannot be broadly generalized, because castration with resultant elevation of LH and regression of ventral glands resulted in perseveration of attention in male and female gerbils.

Animals↗
PubMed1982

Attention and habituation: odor preferences, long-term memory, and multiple sensory cues of novel stimuli.

Investigation of and habituation to novel stimuli are part of exploratory behavior of rodents. They are necessary for assessing the environment in seeking food and sexual partners and in avoiding predators. Male and female gerbils were tested in the stimulus-elicited investigation paradigm in order to address several questions on three issues: (a) Gerbils initially showed preferences for odors of strange male bedding and for odors of home cage bedding and then habituated. There was no preference between these two odors, although they could be discriminated. The complex odor stimulus elicited more response than any of the components tested. (b) Memory of an object or of an odor was demonstrated up to 4 wk later. (c) Sensory deprivation by blinding, anosmizing, or removing somatosensation of the upper snout made only small differences in investigation. The removal of any two of these sensory inputs produced more interference with the response, but all of the gerbils investigated the stimulus. It is concluded that attention to novelty and habituation after repeated exposure are very robust behaviors and are mediated through multiple sensory channels.

Animals↗
PubMed1980

Quantitative analysis of developing epiglottal taste buds in sheep.

Epiglottal taste buds of the sheep increase in number during development, and continue to increase until the epiglottis has reached its adult size. However, since the increase in taste bud numbers is paralleled by increase in the surface area of the epiglottis, the density of taste buds decreases progressively in the fetus and newborn. After birth the density remains relatively constant. From examination of the morphological stages of epiglottal taste bud development, we conclude that taste buds are originally produced by de novo formation, but that further increase in numbers is effected by division of existing, developing taste buds. Because of the large number of taste buds, and the maintenance of their density on the epiglottis, it is concluded that they have an important functional role in upper airway protective reflexes.

Aging↗
PubMedDate not supplied

Adult development: plasticity of stable behavior.

Gerbils in a longitudinal study demonstrated very stable behavior over more than a third of their median lifespan. There was highly significant individual stability of such behaviors as locomotor activity, rearing on the hind legs, latency to jump down from a platform, and marking with the ventral gland for thirteen months of adult life, from six to eighteen months of age. In some of these behaviors, general changes were observed over time, such as increased latency to jump down from a platform. Additionally, brief, outdoor enrichment (one hour a month) resulted in more scent marking than was found in control gerbils. In gerbils tested monthly there was less locomotor activity and rearing on the hind legs than in gerbils tested only once. It was observed that gerbils with a strong tendency to have seizures had more locomotor activity, more rearing, fewer markings, and shorter latency to jump down from a platform than those who rarely seized. Further, when gerbils had a seizure prior to testing, their activity scores and number of rearings were greater than on days when they did not have a seizure. Sex differences are discussed. These normative data provide important knowledge of adult development for comparison with studies of aging changes in gerbils.

Aging↗